How can I override the default plotly_dark template's marker border setting?

Hi, I’m currently unable to override the marker border colour setting present by default in the plotly_dark template/theme. When I use:

fig.update_layout(template='plotly_dark',
                          xaxis=dict(
                              showgrid=False,
                              showticklabels=False),
                          plot_bgcolor='#282828',
                          paper_bgcolor='#282828'
                          )

fig.update_traces(marker=dict(size=10, opacity=0.9,
                              line=dict(width=1,
                                        color='lightgrey')),
                  selector=dict(mode='markers'))

The plotly_dark theme overrides my border/halo lightgrey setting and it’s currently way too dark. How can I get around this problem? I imagine that I can create a custom template but I’m not sure how to update the trace to set the border colour to do so and can’t find anything in the documentation on that. Any ideas? Thanks!

fig[‘layout’][‘template’][‘data’][‘scatter’][0][‘marker’][‘line’][‘color’] = ‘lightgrey’